Long-range acoustic device

A long-range acoustic device (LRAD), acoustic hailing device (AHD), or sound cannon is a specialized loudspeaker and sound weapon that produces sound at high power for communicating at a distance. It has been used as a method of crowd control, which has historically been known to cause permanent hearing damage over long periods, having an extremely high decibel capacity (up to 160 dB measured at one meter from the device).

Source: Wikipedia — Long-range acoustic device (CC BY-SA 4.0)